Study of indoor air quality in school buildings in Argolida’s Sector at the Region of Peloponnese in Greece and potential Health Risks

Aims and scope: Indoor air quality (IAQ) in schools is very important, as students spend more time in school environments besides home. Epidemiological researches have shown that indoor pollutants are associated with several health and respiratory problems. The aim of the present study was to investigate the indoor air quality (IAQ) in school buildings in the Argolida’s Sector at the Region of Peloponnese in Greece. Methods: The study was conducted in fourteen (14) classrooms in a total of seven (7) school buildings in the Argolida’s Sector at the Region of Peloponnese during March 2022 to May 2023. Physical parameters such as temperature (T) and relative humidity (RH) and air pollutants Carbon monoxide (CO), Carbon dioxide (CO2), Nitrogen dioxide (NO2), Volatile Organic Compounds (VOC’s), Particulate matters PM (PM10, PM2.5) were monitored by the series 500 Portable Air Quality Monitor AeroQual, during (1) teaching hour per day in each classroom. Due to governmental measures to protect public health against the risk of further spread of COVID-19, some windows and doors in the classrooms were opened during the samplings. Findings: Mean temperature and relative humidity inside the classrooms was 22,12 oC and 50,87% respectively. The overall mean concentrations of air pollutants recorded inside the schools were 691,35ppm CO2, 0,001ppm NO2, 9,97ppm VOC’S, 15,7μg/m3 PM10 and 11,4μg/m3 PM2.5. No indoor CO concentration (0 ppm) was detected in all classrooms. In this study: a) in all schools (100%) indoor concentration levels of CO2 were below 1000ppm, b) in five (5) of fourteen (14) classrooms (35,7%) in the school buildings were detected concentration levels of CO2 more than 700ppm. In all schools (100%) indoor concentration levels of VOC’s were more than 0,8ppm. Eight (8) classrooms (57,1%) in Argolida’s school buildings had no comfort conditions, due to the high levels of relative humidity (RH>50%). There was a statistically significant difference for temperature (p=0,001), CO2 (p<0,001), NO2 (p=0,006) and VOC’s (p=0,001) between indoor and ambient air. Conclusion: The air quality in school buildings in the Argolida’s Sector was affected by the number of students inside a classroom, the ventilation rate and school’s equipment. The location of schools near central roads and construction activities played role on the concentration of indoor air pollutants. Indoor air pollution (IAP) can lead to potential health risks. The development of monitoring systems for measuring indoor pollutants in schools as well as strategies for control and enhancement of IAQ are considered essential for Public Health

Optimisation and application of a low cost, colorimetric screening method for mercury in marine sediment

A rapid, inexpensive, colorimetric screening method for mercury (Hg) has been optimised to provide a semi-quantitative measurement of Hg concentration in marine sediment within the range 0.038 to 1.5 mg kg-1 encompassing the interim sediment quality guideline (ISQG) value of 0.13 mg kg-1 (CCME 1999) and the probable effects level (PEL) of 0.7 mg kg-1 for Hg in marine sediment (CCME 1999). Neither salinity (up to 41 practical salinity units (psu)) nor sediment organic matter (ΟΜ) content (up to 10%) affected the performance of the method. Accurate results were obtained for spike recovery experiments and analysis of certified reference material (CRM) BCR 580 Estuarine Sediment. The method was applied to sediment samples from Elefsina Bay, Greece. Screening results indicated Hg contamination in the bay, with concentrations exceeding the PEL value. Findings were confirmed by quantitative analysis of the samples by cold vapour atomic absorption spectrometry (CV-AAS), where results in the range 1.4–2.96 mg kg-1 were determined

Indoor air quality in selected school buildings in the Central Sector of Athens at the Attica’s Region and potential Health Risks

Aims and scope: Indoor air pollution is considered as an important environmental risk factor for health. Indoor air quality in schools is very important, as students and teachers spend most of their day (30%) indoors and consequently are more exposed to indoor pollution than outdoor air pollution. The present study has the aim to investigate the indoor air quality (IAQ) in school buildings in the Central Sector of Athens at the Attica’s Region and record physical parameters and concentration levels of indoor air pollutants that are associated with comfort, health and safety conditions inside the classrooms. Methods: The indoor air quality research was conducted in forty-seven (47) classrooms in a total of twenty-six (26) school buildings in the Central Sector of Athens at the Attica’s Region, during the period from March 2022 to May 2023. The air pollutants Carbon dioxide (CO2), Carbon monoxide (CO), Volatile Organic Compounds (VOC’s), Nitrogen dioxide (NO2), Particulate matters PM (PM10, PM2.5) and physical parameters such as temperature (T) and relative humidity (RH) were monitored by the series 500 Portable Air Quality Monitor AeroQual, during (1) teaching hour per day in each classroom. During the samplings some windows and doors were opened, due to measures and recommendations for health and safety for students and teachers against COVID-19. Findings: The overall mean concentrations of the main parameters recorded inside the schools were 0,136 ppm CO, 823,38 ppm CO2, 12,07 ppm VOC’S, 0,006 ppm NO2, 38,1 μg/m3 PM10 and 15,4 μg/m3 PM2.5. The mean recorder temperature was 24,52 oC, and relative humidity was 45,78%. In this study a total number of twenty- two (22) classrooms (46,8%) of schools at the Attica’s Region had no comfort temperatures for students. In all cases indoor CO concentrations were below the 50 ppm, guideline set by WHO. Eight (8) of the forty-seven classrooms in the Region of Attica (17%) had a CO2 concentration more than 1000ppm. VOC’s exceeded the limit value of 0,8ppm indoors in all schools (100%). There was statistically difference for CO, CO2, ΝΟ2 (p<0,001), for VOC’s (p=0,004) and for PM10 (p=0,028)  between indoor and ambient air. Conclusion: The indoor air quality of the classrooms was influenced by the outdoor air, the location of school, the number of windows that were opened during the lesson, the number of students inside the classroom, the activities, furnishing and school equipment. No comfort conditions in classrooms and exceeded limits of indoor air pollutants can lead to diminished IAQ and thereby harmful effects on students. A well airing of the classrooms during the lessons and breaks is necessary for a better air quality. Ventilation is one of the most important factors affecting indoor air quality, diluting the exposure agents originating from indoors

Assessing mercury mobility in sediment of the Union Canal, Scotland, UK by sequential extraction and thermal desorption

The mobility of mercury (Hg) was assessed in sediment from the Union Canal, Scotland, UK. Samples collected from the vicinity of a former munitions factory that manufactured mercury fulminate detonators were subjected to sequential extraction followed by cold vapor atomic absorption spectrometry (CVAAS) and direct analysis using thermal desorption (TD). The sequential extraction indicated that > 75% of mercury (up to 429 mg kg −1 ) was in mobile forms, with 67% of the total Hg content was desorbed in the temperature range 100–250 °C consistent with species weakly attached to the mineral matrix [tentatively identified as an iron (oxy)hydroxide-associated species]. This predominance of mobile mercury species may arise from a lack of association between Hg and either organic matter or sulfur in the sediments. Further investigation of Hg mobilization, transport, and assimilation/biomagnification is required both to determine whether there is a need for remediation of the sediment and to improve understanding of the biogeochemical cycling of Hg in shallow, oxic, freshwater systems

Low-cost colorimetric mercury sensor based on immobilisation of rhodamine B thiolactone in a sustainable agar-agar gel substrate

The global impact of mercury (Hg) pollution requires the development of improved low-cost analytical sensors for Hg determination. Rhodamine B thiolactone (RBT) has been proposed as a colorimetric sensor for Hg2+ as it undergoes ring-opening in the presence of Hg to give a fast, reliable, and easily observed, colour change. In this study a naked-eye biopolymer-based sensor for Hg2+ detection was developed based on RBT-doped agar-agar membranes supported on filter papers. The chromogenic reagent was stable at −18 °C for over two years, whilst the RBT-doped sol–gel membranes prepared from 1% (w/v) agar colloid had a shelf-life of at least 12 weeks at room temperature when stored in the dark. The limit of detection (LOD) for naked-eye sensing was 0.4 μg L−1. For Hg2+ quantification, images of the membranes were recorded using a flatbed scanner and analysed with public-domain ImageJ software. The linear range based on greyscale intensity in the green channel was 0.2–6.0 μg L−1 and the LOD was 0.2 µg L−1. Precision was 10% (n = 3) and spike recoveries were in the range 97–103%. The sensors were regenerated using 10% w/v KI and successfully reused up to 4 times. Compared with other RBT-doped sol–gel sensors, the agar-agar membranes were simpler to prepare, more environmentally friendly, and gave a superior detection limit

Determination and speciation of mercury in sediment and related samples from Greece and Scotland

Mercury is a global pollutant. Research is needed to improve methods for Hg detection and improve understanding of its biogeochemical cycle and risks to human health. In this study, a simple, colorimetric method utilising the reaction of Hg with copper(I)iodide was characterised and adapted for screening marine samples, and the speciation and relationships of Hg with other sediment parameters in contaminated environments was examined. Field application of the colorimetric method indicated Hg concentrations in sediments from West Scotland, U.K., and Kifissos River, Greece, were below Canadian sediment quality guideline values of 0.13 and 0.17 mg/kg for marine and freshwater sediment respectively, whereas sediment from the Falkirk area of the Union Canal, U.K., and Elefsina Bay, Greece, had Hg concentrations above probable effect levels (0.49 and 0.7 mg/kg). Total sediment Hg concentrations, determined quantitatively using cold-vapour atomic absorption spectrometry (AAS), ranged from 0.220 to 2.96 mg/kg in Elefsina Bay. Concentration was influenced by proximity to nearshore pollution sources but was not found to vary seasonally or be related to sediment organic matter content. Sequential extraction indicated that Hg speciation - hence mobility - varied between sites. No Hg was detected in the fish Mugil Cephalus indicating no threat to humans from consumption. Total sediment Hg concentrations in the Union Canal ranged from 22 to 1200 mg/kg. Both sequential extraction and speciation analysis using thermodesorption AAS indicated that ca.>70% of the Hg present was mobile. Analysis by gas chromatography inductively coupled plasma mass spectrometry showed that the methylmercury content was 70% of the Hg present was mobile. Analysis by gas chromatography inductively coupled plasma mass spectrometry showed that the methylmercury content was <0.03% of the total Hg content. A negative relationship was found between total Hg concentration and % methylmercury (r² = 0.60). Ethylmercury was detected in the samples and weak positive relationships determined between methylmercury and ethylmercury and organic matter content, while low pH appeared to favoured the partitioning of methylmercury into the water colum

A rapid colorimetric paper-based screening method for measuring mercury in marine systems

There is considerable current interest in the development of simple, cheap analytical approaches for measuring potentially toxic metals and organometallics in the environment, especially methods that are field-deployable and that can be used by individuals with no scientific training. Amongst the simplest of these are paper-based sensors [1]. These test strips are analogous to litmus paper in that they are impregnated with reagent(s) that change colour on exposure to a specific pollutant, the intensity of which can be estimated ‘by-eye’ or read out by an electronic device, and relates to the pollutant concentration present. Key analytical challenges in the development of such sensors include ensuring that they are selective, sensitive and stable. Such a method has recently been reported for mercury involving reduction of inorganic mercury to elemental mercury and trapping on detecting papers with a copper iodide coating [2]. A preliminary sample digestion procedure is added for the determination of analyte in solid samples. The approach – which has been implemented previously in soil and fresh water sediment – is here evaluated for its applicability in the marine environment. Sensitivity and reproducibility were tested in distilled water, artificial seawater of different salinities, and in real environmental samples. Distinctions could be observed between the responses of solutions whose concentrations differed by at least 20 mg L-1 over a range from 15 – 100 mg L-1, and whose concentrations differed by at least 50 mg L-1 in the range from 100 – 250 mg L-1. The effective detection limit was ~ 15 mg L-1. Salinity ranging from 0-40 psu did not appear to affect significantly the response of the method. The procedure was applied as a screening analysis to provide a preliminary estimate of levels of mercury in contaminated marine sediment obtained from the Gulf of Elefsina, Greece. Sediment samples containing > 100 ng/g mercury were successfully identified, as confirmed by cold vapour atomic absorption spectroscopy

Screening and determination of mobility for mercury in marine sediment

Implementation of a screening method for mercury in the marine environment for the identification of contaminated sediment followed by classification of mobility has been carried out in the Bay of Elefsis, one of the most industrialized areas in the Attica Region of Greece. With releases of mercury being both natural and anthropogenic, and sediment contamination resulting from surface water run off, discharge of industrial effluent, atmospheric deposition and from the aquatic environment itself, the extent of sediment mercury pollution is difficult to assess. Screening involving sample digestion, reduction of inorganic mercury to elemental mercury, and the trapping of elemental mercury on detecting papers with a copper iodide coating, to produce a colour the intensity of which is related to the mercury concentration in the sample has been implemented previously in soil and fresh water sediment [1]. This method was implemented in the marine environment. Marine sediment samples were obtained from the Gulf of Elefsis, both coastal and from the centre of the bay. Industrial discharges in the bay arise mainly from shipyards, steelworks and oil refineries. Coastal sampling points were selected in the region of two shipyards, two in the region of refineries, one from a ship disassembly unit, and one sampling point from an outlet that receives effluent from several industries such as asphalt and paper production. Three samples were also collected from the centre of the bay. Previous determinations of metal concentrations have indicated higher results for coastal regions, consistent with pollution directly as a result of main land industrial activity. Screening results indicate that total mercury concentrations in the majority of the samples exceed 0.1 mg/kg, the method detection limit. There is no agreed international limit value for mercury in sediment. However, subsequent quantification of the mercury concentration in the samples indicated that some exceed the Canadian sediment quality guideline value of 0.13 mg/kg for marine sediment. Determination of the mobility of mercury in the samples was carried out using sequential extraction, identifying mobile, semi mobile and non mobile species concentrations. The mobile fraction was further separated into organic and inorganic forms of mercury using solid phase extraction with sulphydryl cotton fibres [2]

Ecological risk from potentially toxic element legacy contamination in sediment from the Forth and Clyde Canal, Scotland, UK

Industrial activities on the banks of waterways can degrade both the waterbody and the surrounding area and continue to exert pressure on the environment even after the closure of the industries involved. An assessment was undertaken to determine concentration, distribution, mobility and ecological risk of potentially toxic elements (PTE) from legacy contamination in sediments of the Forth and Clyde Canal, UK. Concentrations of PTE, determined by ICP-MS following aqua regia digestion, were 5.54-219 mg kg for As

Optimization and application of a low cost, colorimetric screening method for mercury in marine sediment

A rapid, inexpensive, colorimetric screening method for mercury (Hg) has been optimized to provide a semi-quantitative measurement of Hg concentration in marine sediment within the range 0.038 to 1.5 mg kg(-1) encompassing the interim sediment quality guideline (ISQG) value of 0.13 mg kg(-1) (CCME 1999) and the probable effects level (PEL) of 0.7 mg kg(-1) for Hg in marine sediment (CCME 1999). Neither salinity (up to 41 practical salinity units (psu)) nor sediment organic matter (OM) content (up to 10%) affected the performance of the method. Accurate results were obtained for spike recovery experiments and analysis of certified reference material (CRM) BCR 580 Estuarine Sediment. The method was applied to sediment samples from Elefsina Bay, Greece. Screening results indicated Hg contamination in the bay, with concentrations exceeding the PEL value. Findings were confirmed by quantitative analysis of the samples by cold vapor atomic absorption spectrometry (CV-AAS), where results in the range 1.4-2.96 mg kg(-1) were determined